1. Field: The field of the invention is devices and methods to improve the efficiency of vehicles powered by internal combustion by utilizing energy from the exhaust gases of the engines, and more particularly such devices and methods which enhance the torque applied to the drive shafts of the vehicle by the engines.
2. State of the Art: Increased thermal efficiency of internal combustion engines has been the object of much inventive effort, and recovery of the otherwise wasted energy in the hot exhaust gases has been attempted with some success. The exhaust gases have been used to preheat the fuel before combustion in the engine, to recover some of the thermal energy contained in the hot exhaust gases. The exhaust gases have been used to operate turbines to power superchargers for precompressing the engine intake air. Another approach has utilized the elevated temperatures of the exhaust gases to preheat engine intake air. Preheating of the fuel is inherently dangerous, and only a small portion of the thermal energy in the exhaust gases can be safely used in this manner. The exhaust-powered supercharger systems involve inefficient turbines. Using preheated air is also dangerous, and leads to carburetion problems associated with the heat-expanded air. Thus, effective, safe utilization of the energy in exhaust gases of internal combustion engines has heretofore eluded engine and vehicle designers.